A conventional evaporative control system collects in a charcoal canister the fuel vapor that escapes from a fuel tank. If there is a leak in the fuel tank, canister, or any other component of the evaporative control system, some fuel vapor could escape through the leak into the atmosphere instead of being collected in the canister. Thus, it is desirable to detect leaks.
Leak detection for an evaporative control system is one of several functions that are performed by the IPMA that is disclosed in U.S. patent application Ser. No. 09/542,052, filed Mar. 31, 2000, and which is incorporated by reference herein in its entirety. Briefly, a switch can be activated indicating displacement of a pressure operable device in response to a negative pressure level in a charcoal canister. A properly performing, i.e., sealed, evaporative system should at least maintain the negative pressure level. However, if the evaporative system has a large enough leak, the evaporative system will not maintain switch activation. In an extreme case of a gross leak, no appreciable negative pressure occurs in the evaporative system occurs and the switch activation does not occur. Servicing this IPMA can include verifying switch activity and evaporation system integrity.
It is believed that there is a need to provide an IPMA service tool that can evaluate evaporative control system integrity and verify IPMA switch activity.